That represents an almost 10 per cent increase on the 80,000 genomes currently in genome repositories.

“The real value of these genomes is that many are evolutionarily distinct from previously recovered genomes,” said Professor Tyson, Deputy Director of the Australian Centre for Ecogenomics (ACE).

“They increase the evolutionary diversity spanned by both bacterial and archaeal genome trees by over 30 per cent, and are the first representatives within 17 bacterial and three archaeal phyla.”

Professor Tyson said much microbial diversity remained to be discovered, with the majority of microbes seen under the microscope not being amenable to being grown under laboratory conditions.

“Less than one per cent can be cultured, due to challenging factors including slow growth rates, fastidious growth requirements, and the need to cross-feed off other species,” he said.

However, recent advances in sequencing technology and computational techniques allowed microbial genomes to be recovered directly from environmental samples, bypassing the need for laboratory cultivation.

“The approximately 8000 genomes recovered move us closer to a comprehensive genomic representation of the microbial world, but also show that much remains to be discovered,” he said.

ACE co-researcher Dr Donovan Parks said for the first time, science had the required tools to make substantial inroads into the vast diversity of phylogenetic and metabolic life.

“We anticipate that processing of environmental samples deposited in other public repositories will add tens of thousands of additional microbial genomes to the tree of life,” he said.

“Numerous studies have been reported during the completion of this research which have dozens or hundreds of evolutionarily diverse genomes from varying environments.

“The tools for obtaining genomes from environmental samples are continually improving and we expect that reprocessing the samples considered in this study will result in the recovery of additional genomes.”

“Constructing a comprehensive genomic repository of microbial diversity lays the foundation for furthering our understanding of the role of microorganisms in critical biogeochemical and industrial processes.”